INVESTIGATING THE MECHANISM OF TRANSCRIPTION IN THE PROTIST TETRAHYMENA THERMOPHILA

Candidate: Sydney Pelger
Supervisor: Dr. Jeffrey Fillingham

ABSTRACT

Tetrahymena thermophila (Tetrahymena) is a model organism whose process of transcription has not been widely studied. The research in this thesis is twofold, elucidating the composition of Tetrahymena RNA Polymerase II and the characterization of the oncogenic B-MYB orthologues MybL1 and MybL2. Fixed immunofluorescence demonstrated that RNA Polymerase II is found in the MAC, but also found in the MIC specifically during MIC meiotic prophase. AP-MS discovered that Tetrahymena lack typical RNA Polymerase II composition, where subunits RPB4 and RPB12 are absent. There were multiple interactions of the subunit RPB7 identified, including a possible novel Tetrahymena-specific RNA Polymerase II subunit. Additionally, it was found that MybL1 and MybL2 have differing protein structure and are expressed differently, where only MybL1 is essential for growth. The findings of this thesis contribute to Tetrahymena biology through compositional discovery of RNA Polymerase II and biologically distinguishing between MybL1 and MybL2 function.